JP2018169198A - Electrostatic capacitance measurement device - Google Patents

Abstract

To provide a measurement device configured to correct variations in measured values of electrostatic capacitance due to environmental conditions.SOLUTION: The measurement device includes a base substrate, a first sensor, one or more second sensors, and a circuit board. The first sensor has a first electrode provided along an edge of the base substrate. The one or more second sensors provide one or more second electrodes and are secured on the base substrate. The circuit board is mounted on the base substrate and is connected to the first sensor and the one or more second sensors. The circuit board is configured to apply a high frequency signal to the first electrode and the one or more second electrodes, acquire a first measurement value corresponding to an electrostatic capacitance from a voltage amplitude at the first electrode, and acquire one or more second measurement values corresponding to an electrostatic capacitance from a voltage amplitude at the one or more second electrodes. The measurement device is fixed in the measurement device and has one or more reference surfaces facing the one or more second electrodes.SELECTED DRAWING: Figure 8

Description

  Embodiments of the present disclosure relate to a measuring instrument for measuring capacitance.

  In the manufacture of electronic devices such as semiconductor devices, a processing system for processing a disk-shaped workpiece is used. The processing system includes a transport device for transporting a workpiece and a processing device for processing the workpiece. In general, the processing apparatus includes a chamber body and a stage provided in the chamber body. The stage is configured to support a workpiece placed thereon. The transfer device is configured to transfer the workpiece onto the stage.

  In processing a workpiece in the processing apparatus, the position of the workpiece on the stage is important. Therefore, when the position of the workpiece on the stage is deviated from the predetermined position, it is necessary to adjust the conveying device.

  As a technique for adjusting the transport device, a technique described in Patent Document 1 is known. In the technique described in Patent Document 1, a recess is formed on the stage. Moreover, in the technique described in Patent Document 1, a measuring instrument having a disk shape similar to a workpiece and having an electrode for measuring capacitance is used. In the technique described in Patent Document 1, a measuring instrument is transported on a stage by a transport device, and a measurement value of capacitance depending on the relative positional relationship between the recess and the electrode is acquired, and based on the measurement value. Thus, the conveying device is adjusted to correct the conveying position of the workpiece.

Japanese Patent No. 4956328

  However, in the measuring device for measuring the electrostatic capacity as described above, even if the distance between the electrode for measuring the electrostatic capacity and the object facing it is the same, the temperature, humidity, etc. The measured capacitance value can vary in response to changes in the surrounding environment. Therefore, there is a need for a measuring instrument configured to be able to correct fluctuations in the measured capacitance value due to the environment.

  In one aspect, a meter for measuring capacitance is provided. The measuring instrument includes a base substrate, a first sensor, one or more second sensors, and a circuit board. The first sensor has a first electrode provided along the edge of the base substrate. The one or more second sensors each provide one or more second electrodes and are fixed on the base substrate. The circuit board is mounted on the base board and connected to the first sensor and one or more second sensors. The circuit board applies a high-frequency signal to the first electrode and the one or more second electrodes, acquires a first measurement value corresponding to the capacitance from the voltage amplitude at the first electrode, and the voltage at the one or more second electrodes One or more second measurement values corresponding to the capacitance are obtained from the amplitude. The measuring instrument is fixed in the measuring instrument and has one or more reference surfaces facing one or more second electrodes.

  In the measuring device according to one aspect, the first electrode is provided along the edge of the base substrate. Accordingly, the first measurement value obtained from the voltage amplitude at the first electrode represents a capacitance that reflects the distance between the first electrode and the object existing in front of the first electrode. This first measurement value may vary according to changes in the surrounding environment such as temperature and humidity. In order to be able to correct the variation of the first measurement value according to the environment, the measuring instrument includes one or more second sensors. One or more second electrodes of each of the one or more second sensors face one or more reference surfaces. The one or more second electrodes and the one or more reference surfaces are fixed in the measuring instrument. Therefore, the distance between each of the one or more second electrodes and the corresponding reference surface is constant. Therefore, if there is no change in the surrounding environment, the one or more second measurement values do not change. In other words, the change in the one or more second measurement values reflects a change in the surrounding environment. Based on the fluctuation of the one or more second measured values, the first measured value can be corrected. This modification may be performed on the circuit board or may be performed on a computer device capable of communicating with the measuring instrument.

  In one embodiment, the measuring device includes two second sensors that provide two second electrodes as one or more second sensors, and faces the two second electrodes as one or more reference surfaces, respectively. Two reference planes are provided. A first distance between one second electrode of the two second electrodes and one reference surface facing the second electrode of the two reference surfaces, and the other of the two second electrodes The second distance between the second electrode and the other reference surface of the two reference surfaces facing the other second electrode is different from each other.

  In one embodiment, the circuit board includes a storage element and a computing unit. The storage element is configured to store the first reference value and the second reference value. The first reference value is a second measurement value acquired from the voltage amplitude at one of the second electrodes under a predetermined environment. The second reference value is a second measurement value acquired from the voltage amplitude at the other second electrode under the predetermined environment. The computing unit is obtained from the first difference between the second measured value obtained from the voltage amplitude at one second electrode and the first reference value, and the voltage amplitude at the other second electrode. The correction value is obtained from at least one of the second differences between the second measurement value and the second reference value. In this embodiment, a correction value used for correcting the first measurement value is obtained on the circuit board.

  In one embodiment, the computing unit is configured to calculate an average value of the first difference and the second difference as the correction value. By calculating the average value of the first difference and the second difference, a correction value that can correct the first measurement value with higher accuracy can be derived.

  In one embodiment, the maximum measured value that can be determined from the voltage amplitude at the first electrode, the maximum measured value that can be determined from the voltage amplitude at one second electrode, and the voltage at the other second electrode. The maximum measured value that can be obtained from the amplitude is the same. The first distance is set so that a second measurement value of 20% or more of the maximum measurement value is acquired. The second distance is greater than the first distance. The computing unit selects the first difference as a correction value when the first measurement value is 20% or more of the maximum measurement value, and the first measurement value is 20% of the maximum measurement value. When the value is less than the value, the second difference is selected as the correction value. The magnitude of the first measurement value is inversely proportional to the distance between the electrode and the object. Therefore, the first measurement value varies greatly depending on the distance between the first electrode and the object within a range of 20% or more of the maximum measurement value, and the first measurement value is less than 20% of the maximum measurement value. Fluctuates little with respect to the distance between the electrode and the object. In this embodiment, one of the first difference and the second difference is selected according to the range to which the first measurement value belongs. Therefore, a highly reliable correction value is obtained according to the first measurement value. Therefore, in this embodiment, a correction value that can correct the first measurement value with higher accuracy is obtained.

  In one embodiment, the first distance is 0.6 mm or less.

  In one embodiment, the measuring device includes one second sensor as one or more second sensors, and one reference surface as one or more reference surfaces. The circuit board includes a storage element and a computing unit. The storage element stores a reference value that is a second measured value acquired from the voltage amplitude at the second electrode of one second sensor under a predetermined environment. The computing unit obtains a correction value from the second measured value and the reference value acquired from the voltage amplitude at the second electrode of one second sensor. In this embodiment, a correction value used for correcting the first measurement value is obtained on the circuit board.

  In one embodiment, the computing unit is configured to modify the first measurement value with the correction value. In this embodiment, it is possible to correct the variation of the first measurement value according to the environment in the measuring instrument.

  As described above, there is provided a measuring instrument configured to be able to correct fluctuations in capacitance measurement values due to the environment.

It is a figure which illustrates a processing system. It is a perspective view which illustrates an aligner. It is a figure which shows an example of a plasma processing apparatus. It is a top view which shows the measuring device which concerns on one Embodiment. It is a perspective view which shows an example of a 1st sensor. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. It is sectional drawing taken along the VII-VII line of FIG. It is a top view which shows an example of a 2nd sensor. It is sectional drawing taken along the IX-IX line of FIG. It is a figure which illustrates the structure of the circuit board of a measuring device. (A) of FIG. 11 is a graph showing the relationship between the measured value obtained from the voltage amplitude at the respective electrodes of the first sensor and the two second sensors and the temperature of the ambient environment of the measuring instrument. b) is a graph showing the relationship between the measured value obtained from the voltage amplitude at the respective electrodes of the first sensor and the two second sensors and the humidity of the ambient environment of the measuring instrument. It is a graph which shows the distance dependence of a 1st measured value. It is a figure which shows another example of a 2nd sensor.

  Hereinafter, various embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  First, a processing system having a processing apparatus for processing a workpiece and a transport apparatus for transporting a workpiece to the processing apparatus will be described. FIG. 1 is a diagram illustrating a processing system. The processing system 1 includes tables 2a to 2d, containers 4a to 4d, a loader module LM, an aligner AN, load lock modules LL1 and LL2, process modules PM1 to PM6, a transfer module TF, and a control unit MC. Note that the number of the bases 2a to 2d, the number of the containers 4a to 4d, the number of the load lock modules LL1 and LL2, and the number of the process modules PM1 to PM6 are not limited, and may be any one or more. obtain.

  The bases 2a to 2d are arranged along one edge of the loader module LM. The containers 4a to 4d are mounted on the platforms 2a to 2d, respectively. Each of the containers 4a to 4d is, for example, a container called FOUP (Front Opening Unified Pod). Each of the containers 4a to 4d is configured to accommodate the workpiece W. The workpiece W has a substantially disk shape, for example.

  The loader module LM has a chamber wall that defines a transfer space in an atmospheric pressure state therein. A transport device TU1 is provided in the transport space. The transport device TU1 is, for example, an articulated robot, and is controlled by the control unit MC. The transport device TU1 transports the workpiece W between the containers 4a to 4d and the aligner AN, between the aligner AN and the load lock modules LL1 to LL2, and between the load lock modules LL1 to LL2 and the containers 4a to 4d. It is configured.

  The aligner AN is connected to the loader module LM. The aligner AN is configured to adjust the position of the workpiece W (position calibration). FIG. 2 is a perspective view illustrating an aligner. The aligner AN has a support base 6T, a driving device 6D, and a sensor 6S. The support table 6T is a table that can rotate about the axis extending in the vertical direction, and is configured to support the workpiece W thereon. The support base 6T is rotated by the driving device 6D. The driving device 6D is controlled by the control unit MC. When the support base 6T is rotated by the power from the driving device 6D, the workpiece W placed on the support base 6T is also rotated.

  The sensor 6S is an optical sensor and detects the edge of the workpiece W while the workpiece W is rotated. The sensor 6S determines the amount of deviation of the angular position of the notch WN (or another marker) of the workpiece W from the reference angular position and the amount of deviation of the center position of the workpiece W from the reference position based on the edge detection result. Is detected. The sensor 6S outputs the deviation amount of the angular position of the notch WN and the deviation amount of the center position of the workpiece W to the control unit MC. The controller MC calculates the amount of rotation of the support base 6T for correcting the angular position of the notch WN to the reference angular position based on the deviation amount of the angular position of the notch WN. The controller MC controls the driving device 6D so as to rotate the support base 6T by this amount of rotation. As a result, the angular position of the notch WN can be corrected to the reference angular position. In addition, the control unit MC receives the workpiece W from the aligner AN so that the center position of the workpiece W coincides with a predetermined position on the end effector (end effector) of the transport device TU1. The position of the effector is controlled based on the shift amount of the center position of the workpiece W.

  Returning to FIG. 1, each of the load lock module LL1 and the load lock module LL2 is provided between the loader module LM and the transfer module TF. Each of the load lock module LL1 and the load lock module LL2 provides a preliminary decompression chamber.

  The transfer module TF is connected to the load lock module LL1 and the load lock module LL2 via a gate valve. The transfer module TF provides a decompression chamber that can be decompressed. In the decompression chamber, a transfer device TU2 is provided. The transport device TU2 is, for example, an articulated robot, and is controlled by the control unit MC. The transfer device TU2 is configured to transfer the workpiece W between the load lock modules LL1 to LL2 and the process modules PM1 to PM6 and between any two process modules among the process modules PM1 to PM6. ing.

  The process modules PM1 to PM6 are connected to the transfer module TF via a gate valve. Each of the process modules PM1 to PM6 is a processing apparatus configured to perform a dedicated process such as a plasma process on the workpiece W.

  A series of operations when the workpiece W is processed in the processing system 1 is exemplified as follows. The transfer device TU1 of the loader module LM takes out the workpiece W from any of the containers 4a to 4d and transfers the workpiece W to the aligner AN. Next, the transport device TU1 takes out the workpiece W whose position is adjusted from the aligner AN, and transports the workpiece W to one of the load lock modules LL1 and LL2. Next, one of the load lock modules reduces the pressure in the preliminary decompression chamber to a predetermined pressure. Next, the transfer device TU2 of the transfer module TF takes out the workpiece W from one load lock module, and transfers the workpiece W to any one of the process modules PM1 to PM6. Then, one or more process modules among the process modules PM1 to PM6 process the workpiece W. Then, the transport apparatus TU2 transports the processed workpiece W from the process module to one of the load lock modules LL1 and LL2. Next, the transport device TU1 transports the workpiece W from one load lock module to any of the containers 4a to 4d.

  The processing system 1 includes the control unit MC as described above. The control unit MC may be a computer device including a storage device such as a processor and a memory, a display device, an input / output device, a communication device, and the like. The series of operations of the processing system 1 described above is realized by control of each unit of the processing system 1 by the control unit MC according to a program stored in the storage device.

  FIG. 3 is a diagram illustrating an example of a plasma processing apparatus that can be employed as any one of the process modules PM1 to PM6. A plasma processing apparatus 10 shown in FIG. 3 is a capacitively coupled plasma etching apparatus. The plasma processing apparatus 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The chamber body 12 is made of, for example, aluminum, and an anodizing process can be performed on the inner wall surface thereof. The chamber body 12 is grounded.

  A support portion 14 is provided on the bottom of the chamber body 12. The support part 14 has a substantially cylindrical shape. The support part 14 is comprised from the insulating material, for example. The support portion 14 is provided in the chamber main body 12 and extends upward from the bottom of the chamber main body 12. A stage ST is provided in the chamber S provided by the chamber body 12. The stage ST is supported by the support unit 14.

  The stage ST has a lower electrode LE and an electrostatic chuck ESC. The lower electrode LE includes a first plate 18a and a second plate 18b. The first plate 18a and the second plate 18b are made of a metal such as aluminum, and have a substantially disk shape. The second plate 18b is provided on the first plate 18a and is electrically connected to the first plate 18a.

  An electrostatic chuck ESC is provided on the second plate 18b. The electrostatic chuck ESC has a structure in which an electrode which is a conductive film is disposed between a pair of insulating layers or insulating sheets, and has a substantially disk shape. A DC power source 22 is electrically connected to the electrode of the electrostatic chuck ESC via a switch 23. The electrostatic chuck ESC attracts the workpiece W with an electrostatic force such as a Coulomb force generated by a DC voltage from the DC power source 22. Thereby, the electrostatic chuck ESC can hold the workpiece W.

  A focus ring FR is provided on the peripheral edge of the second plate 18b. The focus ring FR is provided so as to surround the edge of the workpiece W and the electrostatic chuck ESC. The focus ring FR has a first portion P1 and a second portion P2 (see FIG. 6). The first part P1 and the second part P2 have an annular plate shape. The second part P2 is provided on the first part P1. The inner edge P2i of the second portion P2 has a diameter larger than the diameter of the inner edge P1i of the first portion P1. The workpiece W is placed on the electrostatic chuck ESC so that the edge region thereof is located on the first portion P1 of the focus ring FR. The focus ring FR can be formed of a material such as silicon, silicon carbide, or silicon oxide.

  A coolant channel 24 is provided inside the second plate 18b. Refrigerant is supplied to the refrigerant flow path 24 from a chiller unit provided outside the chamber body 12 via a pipe 26a. The refrigerant supplied to the refrigerant flow path 24 is returned to the chiller unit via the pipe 26b. In this way, the refrigerant is circulated between the refrigerant flow path 24 and the chiller unit. By controlling the temperature of the refrigerant, the temperature of the workpiece W supported by the electrostatic chuck ESC is controlled.

  The stage ST is formed with a plurality of (for example, three) through holes 25 penetrating the stage ST. A plurality of (for example, three) lift pins 25a are inserted into the plurality of through holes 25, respectively. In FIG. 3, one through hole 25 into which one lift pin 25a is inserted is depicted. The lift pin 25a is supported by a link that moves up and down by an actuator, for example. The lift pin 25a supports the workpiece W on the tip of the lift pin 25a with its tip protruding above the electrostatic chuck ESC. After that, the workpiece W is placed on the electrostatic chuck ESC when the lift pins 25a are lowered. In addition, after the plasma processing of the workpiece W, the lift pins 25a are lifted to separate the workpiece W from the electrostatic chuck ESC. That is, the lift pins 25a are used for loading and unloading the workpiece W.

  The plasma processing apparatus 10 is provided with a gas supply line 28. The gas supply line 28 supplies the heat transfer gas from the heat transfer gas supply mechanism, for example, He gas, between the upper surface of the electrostatic chuck ESC and the back surface of the workpiece W.

  In addition, the plasma processing apparatus 10 includes an upper electrode 30. The upper electrode 30 is disposed opposite the stage ST above the stage ST. The upper electrode 30 is supported on the upper portion of the chamber body 12 via an insulating shielding member 32. The upper electrode 30 can include a top plate 34 and a support 36. The top plate 34 faces the chamber S, and the top plate 34 is provided with a plurality of gas discharge holes 34a. The top plate 34 can be made of silicon or quartz. Alternatively, the top plate 34 can be configured by forming a plasma-resistant film such as yttrium oxide on the surface of an aluminum base material.

  The support 36 supports the top plate 34 in a detachable manner and can be made of a conductive material such as aluminum. The support 36 may have a water cooling structure. A gas diffusion chamber 36 a is provided inside the support 36. A plurality of gas flow holes 36b communicating with the gas discharge holes 34a extend downward from the gas diffusion chamber 36a. The support 36 is formed with a gas introduction port 36c that guides the processing gas to the gas diffusion chamber 36a, and a gas supply pipe 38 is connected to the gas introduction port 36c.

  A gas source group 40 is connected to the gas supply pipe 38 via a valve group 42 and a flow rate controller group 44. The gas source group 40 includes a plurality of gas sources for a plurality of types of gases. The valve group 42 includes a plurality of valves, and the flow rate controller group 44 includes a plurality of flow rate controllers such as a mass flow controller. The plurality of gas sources of the gas source group 40 are connected to the gas supply pipe 38 via the corresponding valve of the valve group 42 and the corresponding flow rate controller of the flow rate controller group 44, respectively.

  In the plasma processing apparatus 10, a shield 46 is detachably provided along the inner wall of the chamber body 12. The shield 46 is also provided on the outer periphery of the support portion 14. The shield 46 prevents etching by-products from adhering to the chamber body 12 and can be formed by coating an aluminum material with ceramics such as yttrium oxide.

  An exhaust plate 48 is provided on the bottom side of the chamber body 12 and between the support portion 14 and the side wall of the chamber body 12. For example, the exhaust plate 48 may be configured by coating an aluminum material with ceramics such as yttrium oxide. The exhaust plate 48 is formed with a plurality of holes penetrating in the thickness direction. An exhaust port 12e is provided below the exhaust plate 48 and in the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 has a vacuum pump such as a pressure control valve and a turbo molecular pump, and can reduce the space in the chamber body 12 to a desired degree of vacuum. Further, a loading / unloading port 12g for the workpiece W is provided on the side wall of the chamber body 12, and the loading / unloading port 12g can be opened and closed by a gate valve 54.

  The plasma processing apparatus 10 further includes a first high frequency power source 62 and a second high frequency power source 64. The first high frequency power supply 62 is a power supply that generates a first high frequency for plasma generation, and generates a high frequency having a frequency of 27 to 100 MHz, for example. The first high frequency power supply 62 is connected to the upper electrode 30 via the matching unit 66. The matching unit 66 has a circuit for matching the output impedance of the first high-frequency power source 62 with the input impedance on the load side (upper electrode 30 side). Note that the first high-frequency power source 62 may be connected to the lower electrode LE via the matching unit 66.

  The second high-frequency power source 64 is a power source that generates a second high frequency for drawing ions into the workpiece W, and generates a high frequency having a frequency within a range of 400 kHz to 13.56 MHz, for example. The second high frequency power supply 64 is connected to the lower electrode LE via the matching unit 68. The matching unit 68 has a circuit for matching the output impedance of the second high-frequency power supply 64 with the input impedance on the load side (lower electrode LE side).

  In the plasma processing apparatus 10, gas from one or more gas sources selected from among a plurality of gas sources is supplied to the chamber S. Further, the exhaust device 50 sets the pressure in the chamber S to a specified pressure. Further, the gas in the chamber S is excited by the first high frequency from the first high frequency power supply 62. Thereby, plasma is generated. Then, the workpiece W is processed by the generated active species. If necessary, ions may be drawn into the workpiece W by a bias based on the second high frequency of the second high frequency power supply 64.

  Hereinafter, the measuring device will be described. FIG. 4 is a plan view showing a measuring instrument according to one embodiment. The measuring instrument 100 shown in FIG. 4 includes a base substrate 102. The base substrate 102 is made of silicon, for example, and has a shape similar to the shape of the workpiece W, that is, a substantially disk shape. The diameter of the base substrate 102 is the same as the diameter of the workpiece W, for example, 300 mm. The shape and size of the measuring instrument 100 are defined by the shape and size of the base substrate 102. Therefore, the measuring instrument 100 has the same shape as that of the workpiece W and has the same dimension as that of the workpiece W. A notch 102N (or another marker) is formed at the edge of the base substrate 102.

  The base substrate 102 has a lower part 102a and an upper part 102b. The lower portion 102a is a portion located closer to the electrostatic chuck ESC than the upper portion 102b when the measuring instrument 100 is disposed above the electrostatic chuck ESC. The upper portion 102b is a portion having an upper surface exposed upward when the measuring instrument 100 is disposed above the electrostatic chuck ESC.

  The upper portion 102b of the base substrate 102 is provided with a plurality of first sensors 104A to 104H for measuring capacitance. Note that the number of first sensors provided in the measuring instrument 100 may be an arbitrary number of three or more. The number of the first sensors of the measuring device 100 may be one. The plurality of first sensors 104 </ b> A to 104 </ b> H are arranged along the edge of the base substrate 102, for example, at equal intervals along the entire circumference of the edge. Specifically, the front end face 104f of each of the plurality of first sensors 104A to 104H is provided along the edge of the upper portion 102b of the base substrate 102.

  In addition, in the upper portion 102b of the base substrate 102, two second sensors, that is, a second sensor 105A and a second sensor 105B, are provided to enable correction of the measured values of the first sensors 104A to 104H. It is fixed. The second sensor 105 </ b> A and the second sensor 105 </ b> B are disposed at positions separated from each other on the upper surface of the upper portion 102 b of the base substrate 102.

  The upper surface of the upper portion 102b of the base substrate 102 provides a recess 102r. The recess 102r includes a central region 102c and a plurality of radiation regions 102h. The central region 102c is a region that intersects the central axis AX100. The center axis AX100 is an axis that passes through the center of the base substrate 102 in the thickness direction. A circuit board 106 is provided in the central region 102c. The plurality of radiation regions 102h radiate with respect to the central axis AX100 from the central region 102c toward the region where each of the plurality of first sensors 104A to 104H, the second sensor 105A, and the second sensor 105B is disposed. Extends in the direction. The plurality of radiation regions 102h include a plurality of wiring groups 108A to 108H and a wiring group 208A for electrically connecting the plurality of first sensors 104A to 104H, the second sensor 105A, and the second sensor 105B to the circuit board 106. , And a wiring group 208B is provided. The plurality of first sensors 104 </ b> A to 104 </ b> H may be provided on the lower portion 102 a of the base substrate 102.

  Hereinafter, the first sensor will be described in detail. FIG. 5 is a perspective view showing an example of the first sensor. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5 and shows the base substrate and the focus ring of the measuring device together with the first sensor. 7 is a cross-sectional view taken along the line VII-VII in FIG. The sensor 104 shown in FIGS. 5 to 7 is a sensor used as the plurality of first sensors 104A to 104H of the measuring instrument 100, and is configured as a chip-like component in one example. In the following description, an XYZ orthogonal coordinate system is referred to as appropriate. The X direction indicates the front direction of the sensor 104, the Y direction is one direction orthogonal to the X direction and the width direction of the sensor 104, and the Z direction is orthogonal to the X direction and the Y direction. The direction of the sensor 104 is shown.

  As shown in FIGS. 5 to 7, the sensor 104 has a front end face 104f, an upper face 104t, a lower face 104b, a pair of side faces 104s, and a rear end face 104r. The front end face 104f constitutes a front surface of the sensor 104 in the X direction. The sensor 104 is mounted on the base substrate 102 of the measuring instrument 100 so that the front side end face 104f faces the radial direction with respect to the central axis AX100 (see FIG. 4). Further, in a state where the sensor 104 is mounted on the base substrate 102, the front end face 104 f extends along the edge of the base substrate 102. Therefore, when the measuring instrument 100 is disposed on the electrostatic chuck ESC, the front end face 104f faces the inner edge of the focus ring FR.

  The rear side end face 104r constitutes the rear side surface of the sensor 104 in the X direction. In a state where the sensor 104 is mounted on the base substrate 102, the rear end face 104r is located closer to the central axis AX100 than the front end face 104f. The upper surface 104t constitutes the upper surface of the sensor 104 in the Z direction, and the lower surface 104b constitutes the lower surface of the sensor 104 in the Z direction. The pair of side surfaces 104s constitutes the surface of the sensor 104 in the Y direction.

  The sensor 104 has an electrode 143 (first electrode). The sensor 104 may further include an electrode 141 and an electrode 142. The electrode 141 is formed from a conductor. The electrode 141 has a first portion 141a. As shown in FIGS. 5 and 6, the first portion 141a extends in the X direction and the Y direction.

  The electrode 142 is made of a conductor. The electrode 142 has a second portion 142a. The second portion 142a extends on the first portion 141a. Within the sensor 104, the electrode 142 is insulated from the electrode 141. As shown in FIGS. 5 and 6, the second portion 142a extends in the X direction and the Y direction on the first portion 141a.

  The electrode 143 is a sensor electrode formed from a conductor. The electrode 143 is provided on the first portion 141 a of the electrode 141 and the second portion 142 a of the electrode 142. The electrode 143 is insulated from the electrode 141 and the electrode 142 in the sensor 104. The electrode 143 has a front surface 143f. The front surface 143f extends in a direction intersecting the first portion 141a and the second portion 142a. Further, the front surface 143f extends along the front end surface 104f of the sensor 104. In one embodiment, the front surface 143 f constitutes a part of the front end surface 104 f of the sensor 104. Alternatively, the sensor 104 may have an insulating film that covers the front surface 143f on the front side of the front surface 143f of the electrode 143.

  As shown in FIGS. 5 to 7, the electrode 141 and the electrode 142 are open on the side (X direction) of the region where the front surface 143 f of the electrode 143 is disposed and extend so as to surround the periphery of the electrode 143. You may do it. That is, the electrode 141 and the electrode 142 may extend so as to surround the electrode 143 above, behind, and on the side of the electrode 143.

  The front side end surface 104f of the sensor 104 may be a curved surface having a predetermined curvature. That is, the front end face 104f has a constant curvature at an arbitrary position on the front end face, and the curvature of the front end face 104f is the distance between the central axis AX100 of the measuring instrument 100 and the front end face 104f. It can be an inverse number. The sensor 104 is mounted on the base substrate 102 so that the center of curvature of the front end face 104f coincides with the central axis AX100.

  The sensor 104 may further include a substrate portion 144, insulating regions 146 to 149, pads 151 to 153, and via wirings 154. The substrate part 144 has a main body part 144m and a surface layer part 144f. The main body portion 144m is made of, for example, silicon. The surface layer portion 144f covers the surface of the main body portion 144m. The surface layer portion 144f is made of an insulating material. The surface layer portion 144f is, for example, a silicon thermal oxide film.

The second portion 142 a of the electrode 142 extends below the substrate portion 144, and an insulating region 146 is provided between the substrate portion 144 and the electrode 142. Insulating region 146, for _{example, SiO 2, SiN, Al 2} O 3, or are formed of polyimide.

The first portion 141 a of the electrode 141 extends below the substrate portion 144 and the second portion 142 a of the electrode 142. An insulating region 147 is provided between the electrode 141 and the electrode 142. Insulating region 147, for _{example, SiO 2, SiN, Al 2} O 3, or are formed of polyimide.

The insulating region 148 constitutes the upper surface 104 t of the sensor 104. Insulating region 148, for _{example, SiO 2, SiN, Al 2} O 3, or are formed of polyimide. Pads 151 to 153 are formed in the insulating region 148. The pad 153 is made of a conductor and connected to the electrode 143. Specifically, the electrode 143 and the pad 153 are connected to each other by the insulating region 146, the electrode 142, the insulating region 147, and the via wiring 154 that penetrates the electrode 141. An insulator is provided around the via wiring 154, and the via wiring 154 is insulated from the electrode 141 and the electrode 142. The pad 153 is connected to the circuit board 106 via a wiring 183 provided in the radiation region 102h of the recess 102r. Similarly, the pad 151 and the pad 152 are formed of a conductor. The pad 151 and the pad 152 are connected to the electrode 141 and the electrode 142 through corresponding via wirings, respectively. Further, the pad 151 and the pad 152 are connected to the circuit board 106 through corresponding wiring provided in the radiation region 102h of the recess 102r.

The insulating region 149 constitutes the lower surface 104 b of the sensor 104. Insulating region 149, for _{example, SiO 2, SiN, Al 2} O 3, or are formed of polyimide.

  Hereinafter, the second sensor will be described in detail. FIG. 8 is a plan view showing an example of the second sensor. 9 is a cross-sectional view taken along line IX-IX in FIG. The sensor 105 illustrated in FIGS. 8 and 9 is an example of a sensor used as the second sensor 105A and the second sensor 105B. The sensor 105 has the same configuration as the sensor 104 used as the first sensors 104A to 104H. That is, the sensor 105 includes a front end face 104f, an upper face 104t, a lower face 104b, a rear end face 104r, and a front end face 105f, an upper face 105t, a lower face 105b, a rear end face 105r, and a pair of side faces 104s. It has a side surface 105s. The sensor 105 includes an electrode 141, a first portion 141a, an electrode 142, a second portion 142a, an electrode 143, a front surface 143f, a substrate portion 144, a main body portion 144m, a surface layer portion 144f, insulating regions 146 to 149, pads 151 to 153. , And corresponding to the via wiring 154, the electrode 241, the first portion 241a, the electrode 242, the second portion 242a, the electrode 243 (second electrode), the front surface 243f, the substrate portion 244, the main body portion 244m, the surface layer portion 244f, the insulation Regions 246 to 249, pads 251 to 253, and via wiring 254 are provided. The pads 251 to 253 are connected to the circuit board 106 via wirings 281 to 283 provided in the radiation region 102h, respectively.

  The sensor 105 is fixed in the measuring device 100. The sensor 105 is disposed in a recess 102 g formed on the upper surface of the upper portion 102 b of the base substrate 102. The recess 102g provides a reference surface 102s that faces the front end surface 105f of the sensor 105. That is, the measuring instrument 100 provides two reference planes including a reference plane for the second sensor 105A and a reference plane for the second sensor 105B. These two reference planes are fixed in the measuring instrument 100. Therefore, the distance between the reference surface 102s and the electrode 243 (front surface 243f) is also fixed. The reference surface 102s is a curved surface having a predetermined curvature. As an example, the curvature of the reference surface 102s may be the same as the curvature of the inner edge of the focus ring FR. In the illustrated example, a gap is also formed between the inner side surface of the recess 102 g and the side surface 105 s of the sensor 105.

  In one embodiment, the first distance between the reference surface 102s for the second sensor 105A and the electrode 243 (front surface 243f) of the second sensor 105A, the reference surface 102s for the second sensor 105B, and the second The second distance between the electrode 243 (front surface 243f) of the sensor 105B is different from each other. As will be described later, in measuring instrument 100, a measurement value (first measurement value) representing the capacitance is acquired from the voltage amplitude at each electrode 143 of first sensors 104A to 104H. Further, a measurement value (second measurement value) representing the capacitance is acquired from the voltage amplitude at each electrode 243 of the second sensor 105A and the second sensor 105B. Since the first sensors 104A to 104H, the second sensor 105A, and the second sensor 105B have the same configuration, the maximum measurement values that can be acquired from the voltage amplitudes at the respective electrodes of these sensors are the same. In one embodiment, the first distance is set such that a measured value of 20% or more of the maximum measured value provides a voltage amplitude at the electrode 243 of the second sensor 105A. Further, the second distance is larger than the first distance. The first distance is a distance of 0.6 mm or less, for example, and the second distance is a distance of 1.0 mm or more, for example.

  Hereinafter, the configuration of the circuit board 106 will be described. FIG. 10 is a diagram illustrating the configuration of the circuit board of the measuring instrument. As shown in FIG. 10, the circuit board 106 includes a high-frequency oscillator 171, a plurality of C / V conversion circuits 172A to 172H, 272A, 272B, an A / D converter 173, a processor (calculator) 174, a storage device (storage element). 175, a communication device 176, and a power source 177.

  Each of the plurality of first sensors 104A to 104H is connected to the circuit board 106 via a corresponding wiring group among the plurality of wiring groups 108A to 108H. Each of the plurality of first sensors 104A to 104H is connected to the corresponding C / V conversion circuit among the plurality of C / V conversion circuits 172A to 172H via some wirings included in the corresponding wiring group. Yes. The second sensor 105A is connected to the circuit board 106 via the wiring group 208A. The second sensor 105A is connected to the C / V conversion circuit 272A via some wires included in the wire group 208A. The second sensor 105B is connected to the circuit board 106 via the wiring group 208B. The second sensor 105B is connected to the C / V conversion circuit 272B via some wires included in the wire group 208B.

  Hereinafter, each of the first sensors 104A to 104H, each of the second sensors 105A to 105B, each of the plurality of wiring groups 108A to 108H, each of the two wiring groups 208A and 208B, and each of the plurality of C / V conversion circuits 172A to 172H. Each of the two C / V conversion circuits 272A and 272B is referred to as a sensor 104, a sensor 105, a wiring group 108, a wiring group 208, a C / V conversion circuit 172, and a C / V conversion circuit 272, respectively.

  The wiring group 108 includes wirings 181 to 183. One end of the wiring 181 is connected to a pad 151 connected to the electrode 141 of the sensor 104. The wiring 181 is connected to a ground potential line GL connected to the ground GC of the circuit board 106. Note that the wiring 181 may be connected to the ground potential line GL via the switch SWG. One end of the wiring 182 is connected to the pad 152 connected to the electrode 142, and the other end of the wiring 182 is connected to the C / V conversion circuit 172. One end of the wiring 183 is connected to the pad 153 connected to the electrode 143, and the other end of the wiring 183 is connected to the C / V conversion circuit 172.

  The wiring group 208 includes wirings 281 to 283. One end of the wiring 281 is connected to a pad 251 connected to the electrode 241. The wiring 281 is connected to a ground potential line GL connected to the ground GC of the circuit board 106. Note that the wiring 281 may be connected to the ground potential line GL through the switch SWG. One end of the wiring 282 is connected to the pad 252 connected to the electrode 242, and the other end of the wiring 282 is connected to the C / V conversion circuit 272. One end of the wiring 283 is connected to the pad 253 connected to the electrode 243, and the other end of the wiring 283 is connected to the C / V conversion circuit 272.

  The high frequency oscillator 171 is connected to a power source 177 such as a battery, and is configured to receive a power from the power source 177 and generate a high frequency signal. The power source 177 is also connected to the processor 174, the storage device 175, and the communication device 176. The high frequency oscillator 171 has a plurality of output lines. The high-frequency oscillator 171 supplies the generated high-frequency signal to the wiring 182 and the wiring 183 and the wiring 282 and the wiring 283 through a plurality of output lines. Therefore, the high-frequency oscillator 171 is electrically connected to the electrode 142 and the electrode 143 of the sensor 104 and the electrode 242 and the electrode 243 of the sensor 105, and the high-frequency signal from the high-frequency oscillator 171 receives the electrode 142 and the electrode 143. , And are provided to the electrode 242 and the electrode 243.

  A wiring 182 and a wiring 183 are connected to the input of the C / V conversion circuit 172. A wiring 282 and a wiring 283 are connected to the input of the C / V conversion circuit 272. Each of the C / V conversion circuit 172 and the C / V conversion circuit 272 generates a voltage signal representing the capacitance of the electrode connected to the input from the voltage amplitude at the input, and outputs the voltage signal. It is configured. Note that the larger the electrostatic capacitance of the electrode connected to the C / V conversion circuit 172, the larger the voltage of the voltage signal output from the C / V conversion circuit 172 and the C / V conversion circuit 172. Similarly, the larger the electrostatic capacitance of the electrode connected to the C / V conversion circuit 272, the greater the voltage of the voltage signal output from the C / V conversion circuit 272.

  To the input of the A / D converter 173, the outputs of the plurality of C / V conversion circuits 172A to 172H, the C / V conversion circuit 272A, and the C / V conversion circuit 272B are connected. The A / D converter 173 is connected to the processor 174. The A / D converter 173 is controlled by a control signal from the processor 174, and outputs output signals of the plurality of C / V conversion circuits 172A to 172H, the C / V conversion circuit 272A, and the C / V conversion circuit 272B, Convert to digital value. That is, the A / D converter 173 generates a first measurement value representing the capacitance between each electrode 143 of the first sensors 104 to 104H and the object facing the electrode 143. In addition, the A / D converter 173 generates a second measurement value that represents the capacitance between the electrode 243 of the second sensor 105A and the corresponding reference surface 102s. In addition, the A / D converter 173 generates a second measurement value that represents the capacitance between the electrode 243 of the second sensor 105B and the corresponding reference surface 102s. The A / D converter 173 outputs the first measurement value and the second measurement value to the processor 174.

  A storage device 175 is connected to the processor 174. The storage device 175 is a storage device such as a volatile memory, and is configured to store data such as a first measurement value and a second measurement value. The data stored by the storage device 175 may include a correction value and / or a corrected first measurement value which will be described later. Another storage device 178 is connected to the processor 174. The storage device 178 is a storage device such as a nonvolatile memory, and stores a program that is read and executed by the processor 174.

  The communication device 176 is a communication device that complies with an arbitrary wireless communication standard. For example, the communication device 176 is compliant with Bluetooth (registered trademark). The communication device 176 is configured to wirelessly transmit data stored in the storage device 175.

  The processor 174 is configured to control each unit of the measuring instrument 100 by executing the above-described program. For example, the processor 174 supplies high-frequency signals from the high-frequency oscillator 171 to the electrodes 142, 143, 242, and 243, supplies power from the power supply 177 to the storage device 175, and supplies power from the power supply 177 to the communication device 176. Supply etc. are controlled. Further, the processor 174 executes the above-described program to acquire the first measurement value and the second measurement value, store these measurement values in the storage device 175, and the like.

  In one embodiment, the processor 174 of the circuit board 106 may modify a plurality of first measurements, i.e., a first measurement obtained from the voltage amplitude at each electrode 143 of the first sensors 104A-104H. . FIG. 11A shows measured values (measured values MV1 to MV3) acquired from the voltage amplitudes at the electrodes 143 of three first sensors among the plurality of first sensors 104A to 104H, and electrodes of the second sensor 105A. The measured value (measured value MV4) acquired from the voltage amplitude at 243, the measured value (measured value MV5) acquired from the voltage amplitude at the electrode 243 of the second sensor 105B, and the ambient temperature of the measuring instrument 100 It is a graph which shows an example of a relationship. In the graph of FIG. 11A, the ambient environment temperature is set to 10 ° C., 23 ° C., 40 ° C., and 60 ° C. with the humidity of the ambient environment of the measuring instrument 100 set to 40% RH. The measured values obtained when doing so are shown. FIG. 11B shows measured values (measured values MV1 to MV3) acquired from the voltage amplitudes at the electrodes 143 of the three first sensors among the plurality of first sensors 104A to 104H, and the electrodes of the second sensor 105A. The measured value (measured value MV4) acquired from the voltage amplitude at 243, the measured value (measured value MV5) acquired from the voltage amplitude at the electrode 243 of the second sensor 105B, and the humidity of the ambient environment of the measuring instrument 100 It is a graph which shows an example of a relationship. In the graph of FIG. 11B, the ambient environment humidity of the measuring instrument 100 is set to 23 ° C., and the ambient environment humidity is 23% RH, 39% RH, 57% RH, and 76% RH. The measured values obtained when set for each are shown. Note that, in the measurement value acquisition shown in FIGS. 11A and 11B, the measuring device 100 is disposed in a region surrounded by the focus ring FR, and the measuring device 100 and the focus ring FR are connected to each other. The relative positional relationship was not changed. The distance between the electrode 243 of the second sensor 105A and the corresponding reference surface 102s is 0.5 mm, and the distance between the electrode 243 of the second sensor 105B and the corresponding reference surface 102s is 1.0 mm. there were.

  As shown in FIG. 11A, the measurement values (measurement values MV1 to MV5) obtained from the voltage amplitudes at the electrodes of the three first sensors, the second sensor 105A, and the second sensor 105B are measured. The temperature increases as the ambient temperature of the vessel 100 increases. Further, as shown in FIG. 11B, the measurement values (measurement values MV1 to MV5) acquired from the voltage amplitudes at the respective electrodes of the first sensor, the second sensor 105A, and the second sensor 105B are: It increases as the humidity of the surrounding environment of the measuring instrument 100 increases. As is clear from FIG. 11A and FIG. 11B, the variation amounts of the measured values MV1 to MV5 according to the change in the environment around the measuring instrument 100 are substantially the same. Therefore, two second measurement values, that is, a second measurement value obtained from the voltage amplitude at the electrode 243 of the second sensor 105A, and a second measurement value obtained from the voltage amplitude at the electrode 243 of the second sensor 105B. By using at least one of the measured values, it is possible to correct the first measured value of each of the first sensors 104A to 104H.

  In one embodiment, the storage device 175 stores a first reference value that is a second measurement value acquired from the voltage amplitude at the electrode 243 of the second sensor 105A under a predetermined environment (standard environment). Yes. Further, the storage device 175 stores a second reference value that is a second measurement value acquired from the voltage amplitude at the electrode 243 of the second sensor 105B under the standard environment. For example, the temperature in the standard environment is 23 ° C., and the humidity in the standard environment is 40% RH.

  The processor 174 has a first difference (MVa−RVa) between a second measured value (MVa) obtained from the voltage amplitude at the electrode 243 of the second sensor 105A and a first reference value (RVa), and From at least one of the second difference (MVb−RVb) between the second measured value (MVb) acquired from the voltage amplitude at the electrode 243 of the second sensor 105B and the second reference value (RVb). Find the correction value.

  In one embodiment, the processor 174 calculates an average value of the first difference (MVa−RVa) and the second difference (MVb−RVb) as a correction value. In another embodiment, the processor 174 selects the first difference (MVa−RVa) as the correction value when the first measurement value is 20% or more of the maximum measurement value described above, and the first measurement value When the measured value of 1 is less than 20% of the maximum measured value, the second difference (MVb−RVb) is selected as the correction value.

  In one embodiment, the processor 174 modifies the plurality of first measurements using the correction value. For example, the processor 174 subtracts the correction value from each of the plurality of first measurement values (if the correction value is a negative value, the absolute value of the correction value is added to the first measurement value). A plurality of corrected first measurement values are obtained. The plurality of corrected first measurement values are stored in the storage device 175, and transmitted to the control unit MC by the communication device 176. The controller MC corrects the transfer position of the workpiece W of the transfer device TU2 using the corrected first measurement values.

  In another embodiment, the modified plurality of first measurement values may be determined by the control unit MC. In this embodiment, the processor 174 may use the communication device 176 to transmit a plurality of first measurement values and correction values to the control unit MC. The processor 174 may use the communication device 176 to transmit two second measurement values to the control unit MC instead of the correction value. When two second measurement values are transmitted from the processor 174 to the control unit MC, the control unit MC may store the first reference value and the second reference value in advance, or the processor 174 However, the first reference value and the second reference value may be transmitted to the control unit MC using the communication device 176.

  Hereinafter, examples of the first distance and the second distance will be described in detail. As described above, the first sensors 104A to 104H, the second sensor 105A, and the second sensor 105B have the same configuration. Therefore, the maximum measured value that can be obtained from the voltage amplitude at the electrode 143 of each of the first sensors 104A to 104H, the maximum measured value that can be obtained from the voltage amplitude at the electrode 243 of the second sensor 105A, and the first The maximum measured values that can be obtained from the voltage amplitude of the electrode 243 of the two sensors 105B are the same or substantially equal to each other.

  FIG. 12 is a graph showing the distance dependency of the first measurement value. That is, the graph of FIG. 12 shows the relationship between the distance between the electrode 143 of the sensor 104 and the object facing the electrode 143 and the first measurement value. The measurement value measured by the sensor 104 represents the capacitance between the electrode 143 of the sensor 104 and the object facing the electrode 143. The capacitance C is represented by C = εS / d. ε is the dielectric constant of the medium between the electrode 143 and the object, S is the area of the electrode, and d is the distance between the electrode 143 and the object. Therefore, the magnitude of the first measurement value is inversely proportional to the distance between the electrode 143 of the sensor 104 and the object. As shown in FIG. 12, the first measurement value varies greatly depending on the distance between the electrode 143 and the object within a range of 20% or more of the maximum measurement value (1000 a.u.), and the maximum Within a range of less than 20% of the measured value, the distance fluctuates with respect to the distance between the electrode 143 and the object. In view of the distance dependency of the first measurement value, in one embodiment, the first distance is set so that a second measurement value that is 20% or more of the maximum measurement value is acquired. The second distance is set to be larger than the first distance. For example, the first distance is a distance of 0.6 mm or less, and the second distance is a distance of 1.0 mm or more. A correction value that can correct the first measurement value with higher accuracy by setting the distance between the two second sensors and the corresponding reference plane as the first distance and the second distance, respectively. Can be derived.

  The first measurement value acquired from the voltage amplitude at the electrodes 143 of the first sensors 104A to 104H of the measuring instrument 100 can vary according to changes in the surrounding environment of the measuring instrument 100 such as temperature and humidity. This is because, for example, circuit constants in the measuring instrument 100 can change according to changes in the environment around the measuring instrument 100. The measuring instrument 100 includes a second sensor 105A and a second sensor 105B in order to be able to correct the variation of the first measurement value according to the environment. The two electrodes 243 of the second sensor 105A and the second sensor 105B respectively face the two reference surfaces 102s. Since the second sensor 105A, the second sensor 105B, and the two reference surfaces 102s are fixed in the measuring instrument 100, the distance between each of the two electrodes 243 and the corresponding reference surface 102s is constant. is there. Thus, the two second measurements obtained from the voltage amplitudes at the two electrodes 243 do not fluctuate if there is no change in the surrounding environment. In other words, the fluctuations in the two second measurement values reflect changes in the surrounding environment. Based on the fluctuation of the two second measurement values, the first measurement value can be corrected.

  In one embodiment, the correction value used to modify the first measurement value is determined by the processor 174 of the circuit board 106. In one embodiment, a correction value that can correct the first measurement value with higher accuracy can be derived by obtaining an average value of the first difference and the second difference.

  In another embodiment, as described above, the first distance is set to obtain a second measurement value that is 20% or more of the maximum measurement value, and the second distance is greater than the first distance. Set to a large distance. In addition, when the first measurement value is 20% or more of the maximum measurement value, the first difference is selected as the correction value, and the first measurement value is less than 20% of the maximum measurement value. If it is a value, the second difference is selected as the correction value. In this embodiment, one of the first difference and the second difference is selected according to the range to which the first measurement value belongs. Therefore, a highly reliable correction value is obtained according to the first measurement value. Therefore, in this embodiment, a correction value that can correct the first measurement value with higher accuracy is obtained.

  Although various embodiments have been described above, various modifications can be made without being limited to the above-described embodiments.

  For example, in the above embodiment, the reference surface 102s is the inner surface of the recess 102g formed in the base substrate 102, but the reference surface 102s may be provided by an element other than the base substrate 102. FIG. 13 is a diagram illustrating another example of the second sensor. In the example of FIG. 13, the reference wall 250 is fixed inside the recess 102 g formed in the base substrate 102. The reference wall 250 provides a reference surface 250 s that faces the electrode 243. In this example, by adjusting the wall thickness of the reference wall 250, the distance between the electrode 243 and the reference surface 250s can be adjusted.

  The measuring device may include only one of the second sensor 105A and the second sensor 105B. For example, the measuring device may include only the second sensor 105A in order to obtain the correction value. In this case, the storage device 175 of the circuit board 106 stores a reference value that is a second measurement value acquired from the voltage amplitude at the electrode 243 of the second sensor 105A under a predetermined environment. The processor 174 can obtain a correction value from the second measurement value and the reference value acquired by the second sensor 105A. The processor 174 may modify the first measurement value using the correction value.

  DESCRIPTION OF SYMBOLS 100 ... Measuring device, 102 ... Base board | substrate, 104A-104H ... 1st sensor, 105A ... 2nd sensor, 105B ... 2nd sensor, 106 ... Circuit board, 174 ... Processor (arithmetic unit), 175 ... Memory | storage device (memory element) ), 143... Electrode (first electrode), 106... Circuit board, 243.

Claims (9)

A measuring instrument for measuring capacitance,
A base substrate;
A first sensor having a first electrode provided along an edge of the base substrate;
One or more second sensors fixed on the base substrate, each providing one or more second electrodes;
A circuit board mounted on a base substrate and connected to the first sensor and the second sensor, for applying a high frequency signal to the first electrode and the one or more second electrodes, A first measurement value corresponding to the capacitance is obtained from the voltage amplitude, and one or more second measurement values corresponding to the capacitance are obtained from the voltage amplitude at the one or more second electrodes. The circuit board;
With
The measuring device is fixed in the measuring device and has one or more reference surfaces facing the one or more second electrodes.
Measuring instrument. Two or more second sensors providing two second electrodes, respectively, as the one or more second sensors;
As the one or more reference planes, two reference planes respectively facing the two second electrodes,
A first distance between one second electrode of the two second electrodes and one reference surface of the two reference surfaces facing the second electrode; and the two second electrodes. A second distance between the other second electrode and the other reference surface facing the other second electrode of the two reference surfaces is different from each other,
The measuring instrument according to claim 1. The circuit board is
From the first reference value that is the second measurement value acquired from the voltage amplitude at the one second electrode under a predetermined environment, and the voltage amplitude at the other second electrode under the predetermined environment A storage element configured to store a second reference value that is the acquired second measurement value;
Obtained from the first difference between the second measured value obtained from the voltage amplitude at the one second electrode and the first reference value, and the voltage amplitude at the other second electrode. An arithmetic unit configured to obtain a correction value from at least one of the second differences between the second measurement value and the second reference value;
Having
The measuring instrument according to claim 2.   The measuring device according to claim 3, wherein the computing unit is configured to calculate an average value of the first difference and the second difference as the correction value. From the maximum measured value that can be obtained from the voltage amplitude at the first electrode, the maximum measured value that can be obtained from the voltage amplitude at the one second electrode, and the voltage amplitude at the other second electrode The maximum measurement that can be determined is the same,
The first distance is set such that the second measurement value of 20% or more of the maximum measurement value is obtained from the voltage amplitude at the one second electrode;
The second distance is greater than the first distance;
The computing unit selects the first difference as the correction value when the first measurement value is 20% or more of the maximum measurement value, and the first measurement value is the maximum value. The second difference is selected as the correction value when the measured value is less than 20% of the measured value.
The measuring instrument according to claim 3.   The measuring device according to claim 5, wherein the first distance is 0.6 mm or less.   The measuring device according to any one of claims 3 to 6, wherein the computing unit is configured to correct the first measurement value by the correction value. As the one or more second sensors, one second sensor is provided,
As the one or more reference planes, one reference plane is provided,
The circuit board is
A storage element configured to store a reference value that is the second measured value obtained from a voltage amplitude at the second electrode of the one second sensor under a predetermined environment;
An arithmetic unit configured to obtain a correction value from the second measured value and the reference value acquired from the voltage amplitude at the second electrode of the one second sensor;
Having
The measuring instrument according to claim 1. The computing unit is configured to correct the first measurement value by the correction value.
The measuring instrument according to claim 8.

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